A scroll fluid machine is known in the related art as a type of compressor used for air compression, refrigeration, and air-conditioning. A scroll fluid machine typically includes a revolving scroll having a revolving wrap that stands upright on an end plate supported on a drive shaft, and a fixed scroll having a fixed wrap that stands upright on an end plate, wherein the revolving wrap and the fixed wrap are intermeshed such that an enclosed compression chamber is formed between the revolving wrap and the fixed wrap.
In the scroll fluid machine, the drive shaft is caused to revolve eccentrically such that a volume of the compression chamber is gradually reduced in a centripetal direction by a relative motion between the revolving wrap and the fixed wrap. Meanwhile, a fluid suctioned from an outer peripheral portion of the compression chamber is led to a central portion while being compressed, whereupon the compressed fluid is discharged.
In the scroll fluid machine having this configuration, a rotation prevention mechanism that prevents the revolving scroll from rotating by restricting a revolving region thereof is provided to cause the revolving scroll to perform a revolving motion relative to the fixed scroll. A pin crank mechanism is known as a type of rotation prevention mechanism. The pin crank mechanism restricts the motion of the revolving scroll by coupling the revolving scroll side to the fixed scroll side via a pin crank shaft. Patent Document 1, for example, discloses a technique employed in a scroll fluid machine having a pin crank mechanism in which a revolving scroll side pin portion and a fixed scroll side pin portion are provided separately, whereupon the two pin portions are fitted together to form an integrated pin crank shaft.
Further, Patent Document 2 discloses a double wrap type scroll fluid machine that includes a single revolving scroll in which revolving wraps are formed one by one on each of axial direction surface, and a pair of fixed scrolls each having a fixed wrap that is fitted to the respective wraps of the revolving scroll. In a double wrap type scroll fluid machine of this type, the revolving wrap is often supported and restricted in an axial direction using a resin member known as a tip seal.
Furthermore, as a technique employed in a single wrap type scroll fluid machine in relation to a vacuum seal, Patent Document 3, for example, discloses a single wrap type scroll fluid machine in which a P seal (a dust seal), which is similar to a tip seal, is provided on an outermost periphery of a revolving portion separately from a tip seal.
Further, Non-Patent Document 1 discloses a technique for housing a bearing in a large-diameter bellows.
Patent Document 1: Japanese Patent Application Publication No. 2003-201977
Patent Document 2: Japanese Patent Application Publication No. H5-187372
Patent Document 3: Japanese Patent Application Publication No. 2005-320885
Non-Patent Document 1: XDS Scroll Pump, Internet <http://www.edwardsvacuum.com/Products/List.aspx?r=3>